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I was wondering why semi-trucks are called that. Doesn’t semi mean “part of”? A semi-truck is a whole truck if I ever saw one!

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up vote 26 down vote accepted

Semi truck or semi is short for semi-trailer truck. It describes a truck consisting of a tractor and a half-trailer. The trailer is a half-trailer because it does not have wheels both front and back, but only in back. The front is supported by the tractor.

picture of a semi-trailer truck

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Yes, see this link for more explanation. – Jim Aug 2 '12 at 0:12
AKA "tractor trailer" – Bob Aug 2 '12 at 1:14
In Australia we call the pictured contraption (including the truck body) a "semi-trailer", and the truck/tractor bit when referred to separately a "prime mover". – jozzas Aug 2 '12 at 6:39
And in the UK this is called an "articulated lorry", or sometimes just an "artic". – Martin Aug 2 '12 at 7:44
@Martin: or Juggernaut! – e100 Aug 2 '12 at 10:32

protected by Mari-Lou A Jun 9 '14 at 7:01

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